Feeding device



Aug. 19, 1941.

V. E. MCCOY FEEDING DEVICE Filed Nov. 4, 1957 5 Sheets-Sheet 1 Aug. 19, 1941. v. E. McCOY FEEDING DEVICE 3 Sheets-sheaf. 2

Filed NOV. 4, 1937 2!!!! N all! EE EHQH Aug. 19, 1941. v. E. M COY FEEDING DEVICE Filed Nov. 4, 1937 3 Sheets-Sheet 3 Patented Aug. 19, 1941 UNITED STATES PATENT OFFICE FEEDING DEVICE Verl E. McCoy, La Grange, Ill. Application November 4, 1937, SerlalNo.'172,687

1 Claim.

This invention relates to an automatic solution feeding apparatus, and more particularly to a proportional feeding system and pump therefor, arranged to feed one fluid or solution into another fluid in substantially direct proportion to the flow of said second fluid in a suitable conduit.

It is an object of the invention to provide means for proportionally feeding a solution into a fluid pressure conduit in substantially direct proportion to the volume flow of the fluid.

Attempts have been made to use a differential pressure in the fluid system produced by a Venturi tube or other device for producing a vena contracta. However, the differential pressure produced in such a manner does not vary directly with the velocity of the flow, but more nearly as the square of the velocity, so that when such.

devices are used, there is wide variation in-the feed which is not directly proportional to the volume flow in the system.

Various attempts have also been made to use so-called proportional pumps for introducing a solution into a fluid. However, many difliculties have been encountered in that the pumps have not been accurately controlled relative to the volume flow, and these methods have therefore been more or less unsatisfactory.

The present invention provides a solution feeding system and proportional pump therefor, in which the pump may be automatically controlled in direct proportion to the velocity of the fluid, and in such a manner that variations in the velocity cause proportional variations in the operation of the pump whereby the solution injected into the fluid is always substantially in direct proportion to the volume flow.

"It is also an object to provide, in a system of thecharacter described, a pump having an electrical control means, and means for operating the electrical control means in direct proportion to the velocity flow of the fluid in a suitable conduit.

Further objects will be apparent from the spec.- iflcation and the appended claim.

In the drawings:

Fig. 1 is a diagrammatic view of a complete solution feeding system and illustrates one embodiment of theinvention in which a proportiona1 pump may be intermittently operated by pressure from the fluid conduit or from any other suitable pressure source.

Fig. 2 is a diagrammatic view illustrating another embodiment of the invention in which a suitable pump may be operated by a continuously running motor, and in which the intermittent operation may be electrically controlled by the fluid in a pressure conduit.

Fig. 3 is a vertical sectional view through the proportional pump illustrated in Fig. 1.

Fig. 4 is a side elevation of the pump illustrated in Fig. 3.

Fig. 5 is a diagrammatic view of an electrical system for controlling the pump and illustrates a somewhat modifled form of pump and pump control.

Fig. 6 illustrates another slightly modified electrical system for controlling a pump illustrated in Figs. 1, 3, and 4.

Referring to the drawings in detail, the embodiment illustrated in Figs. 1, 3, and 4 comprises a pump having a pump cylinder l and a power cylinder 2 with a suitable piston therein for operating a pump plunger in the cylinder I. The pump is illustrated in detail in Figs. 3 and 4 in which the pump cylinder I is provided with an inlet 3 and an outlet 4. A reciprocating pump plunger 5 is mounted in the cylinder as illustrated, and internally threaded for connection to the piston rod 6 whereby the piston rod 8 and the piston 5 may be relatively adjusted. Lock nuts I are provided for securing the parts in adjusted relationship. The pump cylinder is provided with a suitable packing 8 to prevent leakage around the piston and a drain outlet 9 communicates with the packing 8 in order to prevent air infiltration into the pump cylinder.

The lower end of the plunger 5 is provided with a reduced cylindrical portion I0 which may extend into a corresponding opening il in the cylinder head to provide a shock absorbing cushion ior the piston at the limit of its downward stroke. The inlet 3 is provided with a check valve l2 which is normally retained in closed position by means of a spring l3, but it may be opened by pressure on a plunger H. The outlet 4 is also provided with a check valve IS. A socalled surge chamber l6 may be connected with the outlet of the pump if desired. The piston rod 6 extends into the power cylinder 2 and is provided with a piston head l1. This piston rod is provided with an upwardly extending cylindrical portion l8 which is adapted to enter an opening IS in the upper cylinder head to provide a cushion for the upward stroke of the pump.

The cylinder I8 is provided at opposite ends with ports 20 communicating with the piston the valve chamber.

shown, pressure is applied through the upper port 20 to the upper side of the piston l1, and when the piston valve is moved downwardly, the -upper port may be connected to an exhaust passage and the lower port connected withthe pressure inlet 25 whereby pressure will be applied to the lower end. of the cylinder, and the pump piston will be raised.

When the piston valve 22 is in the position illustrated, the pressure inlet 25 communicates with the power cylinder 2 through the valve chamber 2| and the upper port 20, and the lower port 20 communicates with an exhaust passage 26 adjacent the end of the valve casing. When the position of the valve is reversed, the lower port communicates with the pressure inlet, and the upper port 20 communicates with a corresponding exhaust passage 28 adjacent the top of These exhaust passages 25 communicate with an exhaust outlet 21 by means of a passage 28 illustrated in dotted lines in Fig. 4. It will be apparent that when the piston valve 22 is moved in one direction, the power piston ll will be moved in the opposite direction and cause a corresponding movement of the pump plunger 5.

The stroke of the power piston l1 and the pump piston may be varied by a suitable adjustment of the threaded connection between the connecting rod 6 and the piston 5 so that the capacity of the pump is changed and any desired proportional amount of solution may be pumped at each stroke in accordance with the adjustment of the pump plunger.

When the valve 22 is moved to its extreme downward position, it causes a suction stroke of the pump piston to draw in a charge of solution through the inlet 3 and the check valve I2. In order that no additional power may be required of the pump on the suction stroke, other than that sufiicient to draw in the charge of solution, the piston valve 22 may be provided with a downward extending stem 29, which is positioned in alignment with the end of the plunger l4 of the check valve l2. Therefore when the control valve 22 is moved downwardly to start the upward stroke of the pump piston, the stem 29 automatically opens the check valve l2 against the compression of the spring l3 thereby permitting the solution to freely enter the pump chamber. Whenever the valve 22 is moved to the upward position shown, the pump piston is caused to move downwardly thereby forcing the pump charge out of the pump cylinder through. the check valve l5.

The piston valve 22 is also provided withan upwardly extending rod 30 on which is mounted a portion 3! adapted to provide an armature for a solenoid 32. A disc 33 may be secured to the rod 30'ancl compression spring 34 is provided between the disc and the solenoid 32. It will therefore "be apparent that when the solenoid 32 is energized the valve piston 22 will be raised to the position shown, and when the solenoid is deenergized the piston valve will be moved to its extreme downward position by means of the spring 34.

The pump and other elements of the proportional system may be arranged a illustrated in Fig. l.

That is, the pump inlet 3 may be connectcd to a solution tank 35 by mean of a conduit 36, and the pump outlet 4 may be connected, by means of a conduit 31, to a fluid pressure conduit 38 in which it is desired to inject an amount of solution directly proportional to the volume flow therein. Also the outlet9. adjacent the pump packing 8 may be connected to a return pipe 39 which may communicate with the solution tank 35. The pressure inlet 25 for the power cylinder 2 may be connected by means of a: suitable conduit 40' to the fluid conduit 38 to receive pressure therefrom for operating the pump. However, if desired, the power inlet 42 may be connected to any suitable pressure source. It also will be understood that the pump may be operated by either pneumatic pressure or hydraulic pressure if desired.

'In order to control the solenoid 32 so that the pump will intermittently be operated to inject solution proportional to the volume flow, an electrical circuit comprising conductors 43 may be connected to any suitable source of electrical power, and one of these conductors may be provided with a switch 44 for making and breaking the circuit. This switch preferably comprises the usual mercury tube having contacts therein and which may be pivotally mounted at 45 on a cam lever 46. This cam lever is provided with a roller resting on a cam 41 which is in turn secured to a shaft 48. The shaft 43 may be driven from a suitable flow meter, which in the present embodiment comprises a propeller 49 positioned in the path of the fluid fiow through the conduit 38. The propeller 49 is arranged to rotate the cam shaft 48 by means of suitable beveled gears 50 and 5|, and in accordance with the velocity of the fluid in the conduit 38.

Fig. 2 illustrates another embodiment of the invention in which the pump piston 5 is provided with a piston rod 6a which may be connected to a crank shaft 52 as shown. The crank shaft 52 is driven through a suitable clutch 53 by means of a continuous running motor 54 and a speed reducing mechanism 55. The clutch 53 is normally disengaged and comprises a driving member 56 and a driven member 51. The clutch is preferably of a type which may be automatically controlled to permit only one revolution when desired. In the embodiment illustrated, the clutch comprises the usual dog controlled clutch in which the dog is provided with an outwardly extending arm 58 which normally rests on a detent lever 59 which latter is retained against a stop 60 by means of a spring 6 I. In this position the clutch i disengaged. In order to permit the engagement of the clutch, a solenoid 62 is provided with an armature 63 which is normally held in the position shown by means of a spring 54. The armature is provided with a pawl 65 which is movable with the armature, and which is provided with a slot 66. When the solenoid 62 is energized, the pawl 65 which engages the end of the detent 59 is moved by the armature to release the dog arm 58 and permit the engage- .ment of the clutch. A fixed pin 61 extends into Fig. illustrates a slightly different embodiment in which the piston valve for controlling the pump may entirely be eliminated and the admission of pressure to the power cylinder 2a may be controlled by independent electrically operated valves which selectively control the inlet ports and the exhaust ports. The embodiment shown comprises pressure inlet conduits 68 and 69 and corresponding exhaust outlets 18 and 1|. The pressure inlets are provided with suitable electrically operated valves 12 and 13, and the exhaust outlets are similarly provided with electrically operated valves 14 and 15. These valves may be electrically controlled by suitable solenoids as shown. In the embodiment illustrated, one terminal of each of the solenoids is connected to a suitable conductor 18 and the opposite terminals may be connected to a conductor 11 through suitable switches 18 and 19. The conductors 16,and 11 are connected to any suitable power source. The switches 18 and 19 may be two-way switches of any suitable type, preferably of themercury tube type in which contacts are provided at each end of the tube, and the respective contacts at each end are electrically connected when the tube is tilted in a corresponding direction.

The switches are suitably mounted on a cam lever 48a which may be'pivoted at 45a and the cam lever is provided with a suitable roller resting on the cam 41, which latter is controlled by the flow meter previously described. The solenoid 13a controlling the power inlet valve 13 may be connected to conductor 11 through the conductor 88 and switch 19, and the solenoid 12a controlling the valve 12 may be connected to the conductor 11 by means of conductor 8|, and switch 18, the valves being so positioned relative to the control solenoids that, with the switches in the position shown, the solenoid 12a will be energized and the corresponding inlet valve 12 will therefore be open to admit pressure to the cylinder. Also the solenoid 13a will be deenergized and its con'esponding inlet valve 13 will be closed. The exhaust valve solenoid 14a is connected to the conductor 11 by means of a conductor 82 and switch 18, and the valve solenoid 150 may be connected to the conductor 11 same time the pressure inlet solenoid 19a and the exhaust solenoid 14a are deenergized and their corresponding valves 13 and 14 are closed, and

therefore the piston will remain in its downward position shown, and the pump will not operate until the switches 18 and 19 are tilted in reverse direction. When the switches 18 and 19 are tilted in the opposite direction in response to the operation of the flow meter, the operating conditions of the solenoids will be reversed and therefore the pressure inlet valve 13 and exhaust valve 14 will open, and the pressure inlet valve 12 and the exhaust valve 15 will close and the piston [1 will be raised to provide a suction stroke of the pump. As soon as the switches are again tilted a pressure stroke or the pump will take place, which will inject a charge of solution into the fluid pressure conduit in proportion to the volume flow therein.

Fig. 6 illustrates another embodiment of the invention in which a somewhat modified electrical means is provided for operating the slide piston valve 22 illustrated in Fig. 3. In this embodiment the piston valve is provided with an upwardly extending stem 84 having a piston head 85 thereon operating in a cylinder 86. A compression spring 81 is provided to normally hold the piston in its raised position as shown. The cylinder 86 is provided with a pressure and exhaust passage 88 to which is connected a pressure inlet conduit 89 having a controlling valve 98. An exhaust conduit 9| is also connected to the passage 88 and provided with an exhaust valve 92. The valves 98 and 92 may be provided with solenoids 93 and 94 respectively for operating the valves. One terminal of these solenoids is connected to a suitable electrical power source by means of a conductor 95 and the opposite terminals of the solenoids are connected to a power conductor 98 by means of a two-way switch 91 which is mounted for control by the previously described flow meter in the same manner as shown in Fig. 5.

With the switch 91 m the position illustrated,

in response to the operation of the flow meter,

the condition of the valves is reversed, and the valve 98 will be closed and pressure admitted to force the piston valve downwardly against. the compression of the spring 88. When the switch is tilted in the reverse direction the condition of the valves will again be reversed and the spring 81 will raise the piston.

It will be apparent that the embodiments illustrated in Figs. 5 and 6 are arranged to cause the intermittent operation of the pump directly in proportion to' the velocity of the fluid in the conduit 38 and therefore the solution injected will be directly proportional to the volume flow therein.

Modifications may be made by those skilled in the art, and it is desired therefore that the invention be limited only by the prior art and the scope of the appended claim.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is:

A proportional pump comprising a cylinder, having an inlet and an outlet adjacent one end, a reciprocable' piston in said cylinder, a check valve in said inlet, a check valve in. said outlet, means for intermittently operating said piston, control means for said operating means, and means operated by said control means to open said inlet check valve substantially instantly and simultaneously with the start of the suction stroke of said piston irrespective of the length of stroke, and adjustable means to vary the length of stroke of said piston.

V VERL E. MCCOY. 

